Shan Naz, Hawxwell Samuel M, Adams Harry, Brammer Lee, Thomas Jim A
Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom.
Inorg Chem. 2008 Dec 15;47(24):11551-60. doi: 10.1021/ic8007359.
A family of coordination complexes has been synthesized, each comprising a ruthenium(II) center ligated by a thiacrown macrocycle, [9]aneS(3), [12]aneS(4), or [14]aneS(4), and a pair of cis-coordinated ligands, niotinamide (nic), isonicotinamide (isonic), or p-cyanobenzamide (cbza), that provide the complexes with peripherally situated amide groups capable of hydrogen bond formation. The complexes [Ru([9]aneS(3))(nic)(2)Cl]PF(6), 1(PF(6)); [Ru([9]aneS(3)) (isonic)(2)Cl]PF(6), 2(PF(6)); Ru([12]aneS(4))(nic)(2)(2), 3(PF(6))(2); Ru([12]aneS(4))(isonic)(2)(2), 4(PF(6))(2); Ru([12]aneS(4)) (cbza)(2)(2), 5(PF(6))(2); Ru([14]aneS(4))(nic)(2)(2), 6(PF(6))(2); Ru([14]aneS(4))(isonic)(2)(2), 7(PF(6))(2); and Ru([14]aneS(4))(cbza)(2)(2), 8(PF(6))(2) have been characterized by NMR spectroscopy, mass spectrometry, and elemental analysis. UV/visible spectroscopy shows that each complex exhibits an intense high-energy band (230-255 nm) assigned to a pi-pi* transition and a lower energy band (297-355 nm) assigned to metal-to-ligand charge-transfer transitions. Electrochemical studies indicate good reversibility for the oxidations of complexes with nic and isonic ligands (|I(a)/I(c)| = 1; DeltaEp < 100 mV), In contrast, complexes 5 and 8, which incorporate cbza ligands, display oxidations that are not fully electrochemically reversible (|I(a)/I(c)| = 1, DeltaEp > or = 100 mV). Metal-based oxidation couples between 1.32 and 1.93 V versus Ag/AgCl can be rationalized in term of the acceptor capabilities of the thiacrown ligands and the amide-bearing ligands, as well as the pi-donor capacity of the chloride ligands in compounds 1 and 2. The potential to use these electroactive metal complexes as building blocks for hydrogen-bonded crystalline materials has been explored. Crystal structures of compounds 1(PF(6)).H(2)O, 1(BF(4)).2H(2)O, 2(PF(6)), 3(PF(6))(2), 6(PF(6))(2)CH(3)NO(2), and 8(PF(6))(2) are reported. Four of the six form amide-amide N-H...O hydrogen bonds leading to networks constructed from amide C(4) chains or tapes containing R(2)(2) (8) hydrogen-bonded rings. The other two, 2(PF(6)) and 8(PF(6)), form networks linked through amide-anion N-H...F hydrogen bonds. The role of counterions and solvent in interrupting or augmenting direct amide-amide network propagation is explored, and the systematic relationship between the hydrogen-bonded networks formed across the series of structures is presented, showing the relationship between chain and tape arrangements and the progression from 1D to 2D networks. The scope for future systematic development of electroactive tectons into network materials is discussed.
已经合成了一系列配位化合物，每个化合物都包含一个由硫杂冠大环[9]aneS(3)、[12]aneS(4)或[14]aneS(4)配位的钌(II)中心，以及一对顺式配位的配体，烟酰胺(nic)、异烟酰胺(isonic)或对氰基苯甲酰胺(cbza)，这些配体为配合物提供了能够形成氢键的外围酰胺基团。配合物[Ru([9]aneS(3))(nic)(2)Cl]PF(6)，1(PF(6))；[Ru([9]aneS(3))(isonic)(2)Cl]PF(6)，2(PF(6))；Ru([12]aneS(4))(nic)(2)(2)，3(PF(6))(2)；Ru([12]aneS(4))(isonic)(2)(2)，4(PF(6))(2)；Ru([12]aneS(4))(cbza)(2)(2)，5(PF(6))(2)；Ru([14]aneS(4))(nic)(2)(2)，6(PF(6))(2)；Ru([14]aneS(4))(isonic)(2)(2)，7(PF(6))(2)；以及Ru([14]aneS(4))(cbza)(2)(2)，8(PF(6))(2)已经通过核磁共振光谱、质谱和元素分析进行了表征。紫外/可见光谱表明，每个配合物都表现出一个归属于π-π*跃迁的高强度高能带(230 - 255 nm)和一个归属于金属到配体电荷转移跃迁的较低能带(297 - 355 nm)。电化学研究表明，含有nic和isonic配体的配合物的氧化具有良好的可逆性(|I(a)/I(c)| = 1；ΔEp < 100 mV)。相比之下，含有cbza配体的配合物5和8的氧化显示出不完全的电化学可逆性(|I(a)/I(c)| = 1，ΔEp≥100 mV)。相对于Ag/AgCl，1.32至1.93 V之间的金属基氧化偶合可以根据硫杂冠配体和含酰胺配体的受体能力，以及化合物1和2中氯配体的π供体能力来解释。已经探索了将这些电活性金属配合物用作氢键晶体材料构建单元的潜力。报道了化合物1(PF(6)).H(2)O、1(BF(4)).2H(2)O、2(PF(6))、3(PF(6))(2)、6(PF(6))(2)CH(3)NO(2)和8(PF(6))(2)的晶体结构。六个化合物中的四个形成酰胺-酰胺N-H...O氢键，导致由酰胺C(4)链或包含R(2)(2)(8)氢键环的带构建的网络。另外两个，2(PF(6))和8(PF(6))，通过酰胺-阴离子N-H...F氢键形成网络。探讨了抗衡离子和溶剂在中断或增强直接酰胺-酰胺网络传播中的作用，并给出了一系列结构中形成的氢键网络之间的系统关系，展示了链和带排列之间的关系以及从一维到二维网络的进展。讨论了未来将电活性结构单元系统开发成网络材料的前景。
